The secondary structure model of part of the HIV-1 leader RNA and the tRNA primer are shown

Copyright information:Taken from "The availability of the primer activation signal (PAS) affects the efficiency of HIV-1 reverse transcription initiation"Nucleic Acids Research 2007;35(5):1649-1659.Published online 18 Feb 2007PMCID:PMC1865047.© 2007 The Author(s). Mutant 2L has a 7-nt substitution in the PAS motif and mutant 2R has a substitution on the opposite side of the base-paired PAS domain. The 2L and 2R mutations were combined in the 2LR mutant. The asterisks at position 37–39 of the tRNA mark the position of a cleavage product that is referred to as 1/2 tRNA in .